[kibana] add documentation for alert metricsets

packages/kibana/_dev/build/docs/README.md

@@ -93,4 +93,36 @@ This status endpoint is available in 6.0 by default and can be enabled in Kibana
 | service.id | Unique identifier of the running service. If the service is comprised of many nodes, the `service.id` should be the same for all nodes. This id should uniquely identify the service. This makes it possible to correlate logs and metrics for one specific service, no matter which particular node emitted the event. Note that if you need to see the events from one specific host of the service, you should filter on that `host.name` or `host.id` instead. | keyword |
 | service.version | Version of the service the data was collected from. This allows to look at a data set only for a specific version of a service. | keyword |
 
-{{event "status"}}
+{{event "status"}}
+
+### Cluster actions
+
+Cluster actions metrics documentation
+
+{{fields "cluster_actions"}}
+
+{{event "cluster_actions"}}
+
+### Cluster rules
+
+Cluster rules metrics
+
+{{fields "cluster_rules"}}
+
+{{event "cluster_rules"}}
+
+### Node actions
+
+Node actions metrics
+
+{{fields "node_actions"}}
+
+{{event "node_actions"}}
+
+### Node rules
+
+Node rules metrics
+
+{{fields "node_rules"}}
+
+{{event "node_rules"}}